[kentonv]

> Is it that cost of constructing Cap'n Proto / Protobuf is quite a bit higher than constructing objects defined natively?

I discussed in more detail in reply to your first post, but just to be really clear on this:

No. In fact, for deeply-nested object trees, constructing a Cap'n Proto object can often be cheaper than a typical native object since it does less memory allocation. However, there are some limitations -- see my other reply.

(Constructing Protobuf objects, meanwhile, will usually be pretty much identical to POCS, since that's essentially what Protobuf objects are.)

There is a common myth that Cap'n Proto "just moves the serialization work to object-build time", but ultimately does the same amount of work. This is not true: Although you could describe Cap'n Proto as "doing the serialization at object build time", the work involved is not significantly different from building a regular in-memory object.